# Using Auxiliary Coordinate Systems

You can define new x- and y- axes in your design plane and save them as an auxiliary coordinate system (ACS). You can define several auxiliary coordinate systems and quickly choose any of them to use, as well as the DGN file or view coordinate systems. At any time, you can make one ACS active.

Tip: Auxiliary coordinate systems can be particularly helpful in 3D design, where they facilitate placing elements on planes at different depths and orientations.

Once an ACS is active you can use it with AccuDraw and with precision input key-ins (such as AX= and AD=) to perform precision input with respect to the auxiliary coordinate systems.

You can also use AccuDraw shortcut key-ins to define and activate auxiliary coordinate systems.